Blood-borne seeding by hematopoietic and endothelial precursors from the allantois.
Until now the allantois has not been considered as a hematopoietic organ. Here we report experimental evidence demonstrating the in situ emergence of both hematopoietic and endothelial precursors in the avian allantoic bud. When the prevascularized allantoic bud from a quail embryo was grafted in the coelom of a chicken host, hematopoietic and endothelial cells later were found in the bone marrow of the host. Because the graft was located at a distance from the limb bud, these cells could reach the bone marrow only by the circulatory pathway. This blood-borne seeding may be accomplished by distinct hematopoietic and endothelial precursors, or by hemangioblasts, the postulated common precursors of these two lineages; we consider the latter interpretation more likely. We also show by reverse transcription-PCR that the allantois region expresses very early the GATA genes involved in hematopoiesis and some beta-globin chain genes.
Caprioli
A
A
Institut d'Embryologie cellulaire et moléculaire du Centre National de la Recherche Scientifique et du Collège de France 49bis, av. de la Belle Gabrielle, 94736 Nogent s/Marne cedex, France. caprioli@infobiogen.fr
Jaffredo
T
T
Gautier
R
R
Dubourg
C
C
Dieterlen-Lièvre
F
F
D000482:Allantois / Q000166:cytology*; D000818:Animals; D001853:Bone Marrow / Q000196:embryology; D002642:Chick Embryo; D002678:Chimera; D003370:Coturnix; D004268:DNA-Binding Proteins / Q000235:genetics*; D004730:Endothelium, Vascular / Q000196:embryology*; D050981:Erythroid-Specific DNA-Binding Factors; D050989:GATA2 Transcription Factor; D050990:GATA3 Transcription Factor; D018507:Gene Expression Regulation, Developmental; D005914:Globins / Q000235:genetics; D006410:Hematopoiesis; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; D050981:Erythroid-Specific DNA-Binding Factors; D050989:GATA2 Transcription Factor; D050990:GATA3 Transcription Factor; D015534:Trans-Activators; D014157:Transcription Factors; D005914:Globins